Spark plug



E. LEE

PARK PLUG Filed Jan. 28 1920 r Zu/w lee Patented il/iay 8, 1923.

WILLIAM E. LEE, OF ST. LOUIS, LIISSOUEI, ASSIGNOB, OF ONE-HALF TO LENDALL C. v

CROSBY, OF ST. LOUIS, IEISSOUBI.

SPARK PLUG.

Application filed January 28, 1920. Serial No. 354,654.

To all whom it may concern:

Be it known that I, WILLIAM E. LEE, a citizen of the United States of America, a resident of the city of St. Louis, in the State of Missouri, have invented certain new and useful Improvements in Spark Plugs, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

This invention relates to improvements in spark plugs, the main object being to provide a spark plug having a sparking terminal adapted tomove independently of the holder whereby it is secured, so as to expose different areas at the spark gap.

In the preferred form of the invention,

the sparking terminals are in the form of balls rotatably mounted in sockets, and

2 adapted to turn in response to vibrations to which the plug is ordinarily subjected in service. These balls have continuous, endless sparking surfaces'and when in service the vibrations of the engine result in a cor- 2 sponding vibratory movement at the balls,

whereby an. irregular, jerky, rotary motion is transmitted to the balls. As a consequence, the balls turn in their supporting sockets to expose different sparking surfaces at the spark gap. The sockets are preferably provided with scraping edges engaging therotary balls to remove can bon therefrom. It will, therefore, be understood that the balls are repeatedly shifted 6 to expose different surfaces at the spark gap, thereby avoiding trouble which has heretofore resulted from accumulations of carbon on the sparking points.

Fig. I is a side elevation of a-spark plug 40 embodying the features of this invention.

Fig. II is an enlarged view, partly in section, illustrating the lower portion of the plug.

Fig. III is a bottom view of the plug 4 with the stem at the lower end thereof shown in section.

To illustrate the invention, I have shown a spark plug wherein the outer electrode comprises a hollow shell 1, an L-shaped stem 2 having a vertical arm screwed into the lower end of said shell and provided with a socket 3 in which a ball 4 is mounted. The lower portion of stem 2 is bentto provide a horizontal arm, said arm being threaded to receive the socket 3. An insulator 5 is secured in the shell 1. The lower portion of shell lis threaded to provide which engage the balls.

It will be observed that the balls 4 and 4?.

form the terminals of the inner and outer electrodes, and that these balls are separated to provide a spark gap between them.

vAlthough the tongues 9.are bent inwardly to contact with and confine the balls, said tongues do not rigidlysecure the balls in the sockets. The balls are free to turn in response to vibrations to which the sockets are subjected in service, and an irregular rotary motion istherefore imparted to the balls, as previously pointed out, to expose clean sparking surfaces at the spark gap, at the same time removing carbon from the surfaces of the ballsfthe carbon being removed by the scraping edges of the tongues '9. Y

I claim A spark plug having an outer electrode comprising a shell, an L-shaped stem having a vertical arm screwed into said shell vertical arm, a socket screwed onto said horizontal arm, a terminal in the form of a ball closely confined in said socket but free to turn in response to vibrations of 90. and a horizontal arm extending from said said arm and socket, said socket being provided with scraping edges maintained in engagement with the closely confined ball. and an inner electrode comprising a rod having a socket at one end, a terminal ball closely confined in the last mentionedsocket but free to turn therein, the last mentioned socket having scraping edges maintained in engagement with the'last mentioned ball,

In testimony that I :claim the foregoing I hereunto afiix my signature. 1

WILLIAM E. LEE. 

